1. Field of the Invention
The present invention relates to a central buffer coupling for rail-mounted vehicles having a coupling shaft arranged to be vertically pivotable around a linkage of the railway vehicle body and supporting a coupling head and a device for horizontal resetting to center at its free end, wherein the device for horizontal resetting to center has a center position guide following a horizontal pivoting movement of the coupling shaft around a vertical pivot axis, as well as actuating means for positioning the center position guide together with the functionally-connected coupling shaft at predefined positions or into any position of a given range of pivoting.
2. Description of the Related Art
Such coupling arrangements are essentially known from the prior art and are characterized by enabling the smoothest possible coupling between two central buffer couplings. The device for resetting to center is hereby usually configured such that a resetting to center follows from deflections of the coupling shaft in the horizontal plane and thus the coupling shaft can always be kept in the center position in the center longitudinal plane during the coupling procedure. A great number of resetting systems are known for realizing such a device for resetting to center which affords the setting of the center position in the horizontal plane e.g. hydraulically or by spring action.
To illustrate the principle of resetting to center, FIG. 1 shows a partially cut-away side view of a device 3 for resetting to center as known from the prior art and disclosed for example in EP 1 321 344 A1. This device 3 for resetting to center, pivotably affixed by means of a coupling shaft 2 to a railway vehicle central buffer coupling, exhibits a center position guide 4 following the pivoting movement of the coupling shaft 2 around its vertical pivot axis which is tensionally-locked to actuating means 5 by means of a gearing.
Specifically, the center position guide 4 in the coupling arrangement according to FIG. 1 is configured as a cam plate pivotally supported at the linkage 1 of the coupling arrangement by means of a vertically attached swivel pin 14. Cam plate 4 is coupled to coupling shaft 2 in a synchronously rotating manner and swivel pin 14 is arranged axially aligned to a bearing bolt 15 of coupling shaft 2. Swivel pin 14 itself is functionally connected to bearing bolt 15 while cam plate 4 is fixedly connected to a gear 16 arranged below said cam plate 4 which itself is connected with and can be driven by an actuating means of the device 5 for resetting to center by a gearing 17 serving as an adjusting drive.
Arranging multi-stage buffer systems on the underframe of railway vehicles is furthermore known from rail-mounted vehicle technology. These devices usually have a reversible buffer system as the primary stage, integrated in the form of, for example, a coupling spring in the coupling shaft and which absorb forces of shock occurring during travel, switching and coupling operations. It is also possible to provide drawgear/shock mechanisms at the bearing for the linkage with which the coupling shaft is attached to the underframe of the vehicle body. The drawgear/shock mechanisms provided in the linkage absorb tractive/compressive forces up to a defined magnitude and transfer the forces undamped therefrom to the vehicle underframe via the bearing.
While drawgear/shock mechanisms do absorb the tractive/impactive forces which occur between the individual vehicle bodies during normal travel, when exceeding operational load, however, for instance in the case when the vehicle impacts an obstacle, it is possible that the coupling's given absorption of energy will not be sufficient. The excess impact energy is then transferred directly to the vehicle underframe. In the process, same is subject to extreme loads such that the vehicle body runs the risk of being damaged or derailed.
One approach to preventing such a situation provides for, in addition to drawgear/shock mechanisms, a further (secondary) buffer system, for example in the form of two side buffers at the outer edge of the front of the respective vehicle body to absorb the impact energy resulting from excessive slack impacts. It is also possible, after the primary buffer system has been fully tapped, to divert residual energy through a predetermined break point in the coupling linkage to buffer elements on the vehicle body, for example friction elements.
This so-called overload protection serves as additional protection against damage resulting from shocks to the vehicle underframe upon strong rear-end collisions. To reduce the impact energy, the coupling with the linkage as well as the center position device is first pushed to the rear out of the coupling plane and thus removed from the force flux transferred between two neighboring vehicle bodies. For example, it is conceivable that after exceeding a critical impact force, the linkage of the coupling arrangement shears off at predetermined break points and larger components of the coupling are moved into an area of the vehicle body's underframe by a crossbar disposed at the front of the vehicle body.
However, with coupling arrangements affixed to the vehicle body by means of a linkage having a center position device, such an overload protection presupposes the corresponding configuration to the connecting plate (crossbar) at which the coupling arrangement linkage is tensionally-locked to the vehicle body, the underframe of the vehicle body respectively, and by means of which in the event of a crash; i.e., upon extreme impact force, the linkage with the center position device and the coupling shaft are pushed through after the response of the shearing elements. The term “shearing elements” here refers to connective elements which in “normal” traveling operation connect the linkage and thus, the coupling arrangement to the connecting plate or the vehicle body, and which lose their function as connective elements after a definable critical impact/tractive force has been exceeded, so that the linkage with the center position device and the coupling shaft as need be, will be pushed into an area provided for this purpose at the underframe of the vehicle body by the connecting plate of the vehicle body.
The disadvantage to this known prior art solution can be seen in that the crossbar disposed at the front of the vehicle body and serving as the connective member needs to be of relatively wide and tall configuration, since in the event of a crash and after the shearing elements response, not only the linkage but also the entire center position device needs to be moved backward and pushed by the crossbar, thus meaning a relatively large effective contact area is needed for the crossbar. In configuring the crossbar, the corresponding connective members respectively, for such a coupling arrangement, it is therefore necessary to design the crossbar accordingly, which results in increased weight to the connective members and especially the coupling arrangement as a whole.